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Aromatic Chemicals by Iron‐Catalyzed Hydrotreatment of Lignin Pyrolysis Vapor
Author(s) -
Olcese Roberto Nicolas,
Lardier George,
Bettahar Mohammed,
Ghanbaja Jaafar,
Fontana Sébastien,
Carré Vincent,
Aubriet Frédéric,
Petitjean Dominique,
Dufour Anthony
Publication year - 2013
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201300191
Subject(s) - coke , catalysis , lignin , pyrolysis , chemistry , chemical engineering , toluene , hydrodeoxygenation , phenol , benzene , anisole , organic chemistry , selectivity , engineering
Lignin is a potential renewable material for the production of bio‐sourced aromatic chemicals. We present the first hydrotreatment of lignin pyrolysis vapors, before any condensation, using inexpensive and sustainable iron–silica (Fe/SiO 2 ) and iron‐activated carbon (Fe/AC) catalysts. Lignin pyrolysis was conducted in a tubular reactor and vapors were injected in a fixed bed of catalysts (673 K, 1 bar) with stacks to investigate the profile of coke deposit. More than 170 GC‐analyzable compounds were identified by GCxGC (heart cutting)/flame ionization detector mass spectrometry. Lignin oligomers were analyzed by very high resolution mass spectrometry, called the “petroleomic” method. They are trapped by the catalytic fixed bed and, in particular, by the AC. The catalysts showed a good selectivity for the hydrodeoxygenation of real lignin vapors to benzene, toluene, xylenes, phenol, cresols, and alkyl phenols. The spent catalysts were characterized by temperature‐programmed oxidation, transmission electron microscopy (TEM), and N 2 sorption. Micropores in the Fe/AC catalyst are completely plugged by coke deposits, whereas the mesoporous structure of Fe/SiO 2 is unaffected. TEM images reveal two different types of coke deposit: 1) catalytic coke deposited in the vicinity of iron particles and 2) thermal coke (carbonaceous particles ≈1 μm in diameter) formed from the gas‐phase growth of lignin oligomers.